Supporters of the Tampa Bay Buccaneers, a once-elite NFL franchise now relegated to a place among American football’s also-rans, would probably not call Malcolm Glazer’s 19-year ownership of the club an unqualified success.

Attendances at games, which have been sliding for years, are the second lowest in the sport. It has been seven years since the team’s last playoff appearance and 12 since its most recent playoff victory, which led to the 2002 Super Bowl that remains the Bucs’ solitary championship moment. And the team’s paltry four victories in 2013, a year that began with high expectations but turned out to be Glazer’s last as its owner, was three fewer than the disappointing 2012 season that preceded it.

Yet as a business venture Glazer’s purchase of the club in 1995 for just $192m (£115m) was a master stroke. In two decades the man who made his $4.4bn fortune largely by investing in real estate, particularly dozens of shopping malls across the US, saw the value of his franchise soar to almost $1.1bn, according to the latest figures from Forbes – enough of a profit to soften the team’s correlating decline on the field.

Much of the criticism levelled over the years by Bucs’ supporters at Glazer, and subsequently his three sons Bryan, Edward and Joel, the club’s co-chairmen, relate to allegations of chronic under-investment.

After effectively strong-arming the taxpayers of Hillsborough county in 1995 into paying to build Tampa’s 66,000-seat Raymond James Stadium, by opening talks with other cities outside Florida about relocating the club, Glazer made some personnel moves that paid off.

Head coach Tony Dungy led the Buccaneers to three playoff appearances in five years and was succeeded by Jon Gruden, architect of the mesmeric 2002 Super Bowl victory over the Oakland Raiders.

But Gruden fell out with general manager Rich McKay and amid the off-field turmoil the Bucs’ immediate post-Super Bowl years were losing ones. Glazer always preferred to leave the running of his franchise to others and when the Buccaneers most needed a steady hand at the rudder it was missing.

Every time since when the team appeared to be close to returning to former glories, notably divisional championships in 2005 and 2007, disappointment followed. Interestingly some of the Buccaneers’ worst-performing years in Glazer’s reign, and the falling from the elite top 10 NFL franchises in the Forbes rankings, followed the completion of his acquisition of Manchester United in 2005. That prompted further criticism from some quarters that the Glazer family was concentrating more on its new pet project across the pond, enjoying five Premier League titles at Old Trafford while depriving the Buccaneers of the investment and big-name signings that could lead to another run at a Super Bowl.

The criticism was mostly unfair. In victory or defeat the reclusive Glazer was passionate about both his franchises, family and friends say. Before his 2006 strokes he regularly eschewed private jets to fly commercially from the family’s Palm Beach enclave to attend Buccaneers games.

Despite everything Glazer is still considered by many in the Tampa Bay area as the man who rescued the franchise from oblivion, and his hands-off approach has been praised by those who worked for him and those who paid at the turnstiles.

“He was responsible for the Buccaneers turning the corner, building the new stadium. He improved everything about the organisation, from their image to their colours to their reputation. He was a genuine, hard-working, one-of-a-kind man. He was a friend, a trailblazer and I'll miss him,” Gruden told the Tampa Bay Times.

Roger Goodell, the commissioner of the NFL, was equally magnanimous. "Malcolm Glazer was the guiding force behind the building of a Super Bowl-champion organisation," he said in a statement.

“His commitment to the Bucs, the NFL and the people of the Tampa Bay region are the hallmarks of his legacy.”